Effect of stress on the corrosion behavior of a near-β titanium alloy in 3.5wt.% NaCl solution

Abstract

The corrosion behavior in 3.5wt.% NaCl solution under different stresses of a near-β titanium alloy with three microstructures, single-phase β (CS1), fine α+β (CS2), and coarse α+β (CS3), was investigated. Electrochemical tests showed that the corrosion resistance in the unstressed condition followed the order of CS1 > CS2 > CS3. After applying stresses of 80% and 90% yield strength, the capacitive loop radii and low-frequency impedance moduli of all three microstructures decreased significantly, accompanied by a negative change in potential and a higher current density. The degree of corrosion resistance deterioration exhibited a direct relationship with the degree of stress. The applied stress disrupted the stability of the passive oxide film, increased the number of surface active sites, and accelerated the anodic substrate dissolution. Under identical stress levels, the single-phase β microstructure CS1 consistently maintained the best corrosion resistance.